RU2446502C2 - Overvoltage protection device with movable contact comprising selective disconnection facility - Google Patents

Abstract

FIELD: electricity.

SUBSTANCE: overvoltage protection device (1) comprises a voltage surge limiter (2) and a disconnecting device (3) with electric contacts (4, 6). The disconnecting device comprises the first connecting electrode (40), electrically connected with the first contact site (41), the second connecting electrode (50), electrically connected with the second contact site (51), and the third switching electrode (60), electrically connected with the second contact site (51). The actuating mechanism (7) moves the third electrode (60) for forced execution of permanent opening of electric contacts (4, 6). The protection device comprises a disconnector (9) from short-circuit currents connected in series between the third electrode (60) and the second contact site (51). The disconnector is switched off from the circuit, when the electric arc (100) is thrown over between the first connecting electrode (40) and the second connecting electrode (50).

EFFECT: improved efficiency of short-circuit protection.

16 cl, 11 dwg

Description

FIELD OF TECHNOLOGY

The present invention relates to an overvoltage protection device comprising a voltage surge protector with non-linear elements varying with voltage, and a tripping device with electrical contacts arranged electrically in series with the voltage surge protector. The electrical device comprises a first connecting electrode electrically connected to the first contact pad, a second connecting electrode electrically connected to the second contact pad, and a third movable arc switching electrode electrically connected to the second contact pad. The actuator moves the third movable arc switching electrode to force the permanent opening of the electrical contacts when electric currents flowing through the protection device have an energy higher than the opening threshold.

BACKGROUND OF THE INVENTION

Known devices for overvoltage protection, containing a surge protector with non-linear elements that vary with voltage, and a tripping device with contacts driven by an actuator. A surge protector and a tripping device are connected in series.

The disconnecting device with contacts disclosed in EP0441722B1 may occupy an opening position and a closing position, respectively, representing an open state and an on state of contacts. The actuator forces the contacts of the disconnecting device to move to the off state, in particular, in case the voltage limiter is rendered unusable when the end of life of nonlinear elements comes.

The disconnecting device with contacts calibrate:

- on the one hand, in order to provide wave electric currents of lightning type 10/350 or 8/20 with the ability to flow without actuating the actuator, and

- on the other hand, to actuate the actuator and to force the continuous opening of the contacts from alternating short-circuit currents.

Contacts can, as a rule, open (repulse) and close when a lightning discharges without releasing the actuator. Such repulsion (opening) of the contacts during the operation of the protection device is followed by automatic re-closure of the contacts. The term "continuous opening" of the contacts understand the opening caused by the actuator. Contact closure is only possible with deliberate external user intervention.

The calibration of the known protection devices is carried out, in fact, in such a way that the actuator of the disconnecting device remains fixed in the presence of wave electric currents of lightning type 10/350 or 8/20. It is usually undesirable for the actuator of the disconnecting device to unlock and forcibly execute a constant opening of the contacts each time a wave electric current of lightning flows through the disconnecting device.

The energy threshold of opening depends directly on the wave electric currents of lightning type 10/350 or 8/20, at which it is undesirable to open the contacts of the disconnecting device.

Alternating short-circuit currents having electrical energy higher than the threshold opening energy cause the contacts of the disconnecting device to open.

With wave electric currents of lightning like 10/350 or 8/20, which have an energy lower than the threshold opening energy, the protection device acts efficiently and allows wave electric currents of lightning to flow, while their energy does not cause significant damage. In addition, wave electric currents of lightning type 10/350 or 8/20, having an energy lower than the "threshold opening energy", do not unlock the actuator of the disconnecting device and, accordingly, do not cause the contacts to open.

However, in some specific circumstances, known protection devices do not provide an adequate level of protection.

Indeed, when the energy of alternating short-circuit currents becomes lower than the threshold breaking energy, the actuator is no longer actuated and does not force the contacts of the disconnecting device to move from the on state to the off state. In this case, the risk of damage to the elements is not negligible.

This situation may, in particular, arise when:

- the impedance of the surge protector becomes lower after receiving multiple lightning strikes. Then a “weak alternating short circuit current” flows in the protection device with an energy lower than the threshold opening energy,

- perform improper installation of the protection device, in particular, when the protection device, usually included between the phase and the neutral, is included, for example, between two phases. The voltage to be switched between the phases is usually higher than the voltage that the surge protector can continuously withstand. Then, the surge protector is turned on, and a “weak alternating short circuit current” flows in the protection device. This weak alternating short circuit current can be reduced if the energy of the power transformer is small, and / or when the cable lengths are large.

In both situations described above, a weakened short-circuit current having an energy lower than the threshold breaking energy can cause significant damage.

SUMMARY OF THE INVENTION

The present invention is to eliminate the disadvantages of modern technical devices by creating a surge protection device containing a disconnecting means that effectively acts as protection against short circuits.

The problem is solved by creating a surge protection device, which in accordance with the invention contains a disconnector for weak alternating short-circuit currents, connected in series between the third movable arc switching electrode and the second contact pad. The disconnector is disconnected from the circuit when the electric arc is transferred between the first connecting electrode and the second connecting electrode, and the disconnector switches from the switched on electric state to the disconnected electric state when alternating electric short-circuit currents flow through this disconnector with an energy lower than the threshold breaking energy.

In a preferred embodiment, the weak AC short-circuit breaker is a thermal disconnector.

Preferably, the thermal switch is a fuse.

According to a preferred embodiment of the invention, the surge suppressor is connected in series with the disconnector for weak alternating short-circuit currents between the third movable arc switching electrode and the second contact pad, while the limiter and disconnector are simultaneously disconnected from the circuit when an electric arc is transferred between the first connecting electrode and a second connecting electrode.

According to a preferred embodiment of the invention, the voltage surge suppressor is electrically connected in series with the disconnecting device of the at least one fuse jumper, the drive means exerting force to move the voltage surge suppressor in case of at least one fuse junction, while moving the said limiter acts directly on the actuator to move the third movable arc switching electrode and when uditelnogo performance permanent opening of the contacts.

Preferably, the drive means comprises a spring.

In a specific embodiment, the voltage surge protector is electrically connected to the second terminal pad with two fused bridges, the first fused jumper intended for a disconnector for weak alternating short-circuit currents, and the second fused jumper melts in case of overheating of the limiter.

Preferably, the second fusible link is a low-melting weld, the surge protector comprises a variable resistor.

Preferably, the surge suppressor comprises a variable resistor connected in series with the spark gap.

In a specific embodiment, a high-current disconnector is connected in series between the first connecting electrode and the first contact pad, while the high-current disconnector acts on the actuator to move the third movable arc switching electrode and force the permanent opening of the electrical contacts.

Preferably, the high current disconnector is calibrated to act on the actuator when electric currents flowing through the disconnector have an energy higher than the threshold opening energy.

Preferably, the high current disconnector comprises an electromagnetic trip means.

Preferably, the high current disconnector comprises a fusible element.

Preferably, the third movable arc switching electrode is connected to the first connecting electrode by an insulating part forming a spark gap when the electrical contacts are closed.

Preferably, the third movable arc switching electrode is in contact with the first connecting electrode when the electrical contacts are closed.

Preferably, the weak AC short circuit breaker is disconnected from the circuit when the third movable arc switching electrode moves away from the first connecting electrode, and an electric arc is transferred between the first connecting electrode and the second connecting electrode.

BRIEF DESCRIPTION OF THE DRAWINGS

Other advantages and features are illustrated by the following description of specific embodiments of the invention, given by way of non-limiting examples with reference to the accompanying drawings, in which:

figure 1 depicts a protection device in accordance with the first preferred embodiment of the invention in the locked position;

figure 2 - protection device in the process of opening, according to the invention;

figure 3 - protection device in the open position, according to the invention;

4 is a protection device in accordance with a second preferred embodiment of the invention in the closed position according to the invention;

5 is a protection device in the process of opening, according to the invention;

6 is a protection device in the open position, according to the invention;

7-9 is a first alternative embodiment of a security device in accordance with various embodiments of the invention;

10-11 are schematic views of alternative embodiments of a protection device in accordance with various embodiments of the invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The surge protection device 1 (Figs. 1-6) comprises a voltage surge suppressor 2 with non-linear elements that vary with voltage, and a tripping device 3 with electrical contacts 4, 6. A voltage surge suppressor 2 and a tripping device 3 are connected in series.

The surge protector 2 preferably comprises a variable resistor 21. In some embodiments of the invention (FIGS. 10 and 11), a spark gap 22 may also be installed in series with the variable resistor 21.

The disconnecting device 3 comprises a first connecting electrode 40 electrically connected to the first contact pad 41, and a second connecting electrode 50 electrically connected to the second contact pad 51.

If the protective device 1 is connected between the phase and the neutral, the contact pads 41, 51 are configured to connect, respectively, to the phase and neutral, or vice versa.

If the protection device 1 is connected between the phase and ground, the pads 41, 51 are configured to connect, respectively, to the phase and ground or vice versa.

The disconnecting device 3 comprises a third movable arc switching electrode 60 electrically connected to the second contact pad 51.

The first electrical contact 4 is located on the first connecting electrode 40, and the second electrical contact 6 is located on the third movable arc switching electrode 60.

According to one embodiment, the third movable arc switching electrode 60 (FIGS. 1-6) is in contact with the first connecting electrode 40 when the electrical contacts 4, 6 are closed.

The disconnecting device 3 further comprises an actuator 7. Said mechanism 7 is arranged to be actuated to move the third movable arc switching electrode 60 and to force the permanent opening of the electrical contacts 4, 6.

The disconnecting device 3 with contacts 4, 6 is calibrated so that, on the one hand, to allow wave electric currents of type 10/350 or 8/20 lightning to flow without actuating the actuator 7 and, on the other hand, actuate the actuator 7 and force the continuous opening of contacts 4, 6 from alternating short circuit currents.

The calibration of the protection devices 1 is carried out in such a way that the actuator 7 of the disconnecting device 3 remains fixed in the presence of wave electric currents of lightning type 10/350 or 8/20. The actuator 7 does not actually perform forced permanent opening of the contacts every time when wave electric currents of lightning flow through them.

The opening energy threshold depends directly on the wave electric currents of lightning type 10/350 or 8/20, in which the opening of contacts 4, 6 of the disconnecting device 3 is not desirable.

When electric currents having an energy higher than the opening energy threshold flow through the protection device, the actuator 7 drives and moves the third movable arc switching electrode 60, and forcibly performs a constant opening of the electrical contacts 4, 6. The electric currents driving the actuator mechanism 7 are usually alternating short circuit currents.

When wave electric currents of lightning of the type 10/350 or 8/20 flow through the protection device, having an energy lower than the threshold opening energy, the protection device is effective and allows wave electric currents of lightning to flow, while their energy does not cause significant damage. In addition, wave electric currents of lightning do not unlock the actuator of the disconnecting device and, accordingly, do not cause forced opening of the contacts.

The overvoltage protection device comprises a disconnector 9 for weak alternating short circuit currents.

In accordance with all preferred embodiments, a low-voltage short circuit disconnector 9 is connected in series between the third movable arc switching electrode 60 and the second terminal pad 51.

When wave electric currents of lightning like 10/350 or 8/20 flow through the protection device, the electric arc 100 very quickly transfers between the first connecting electrode 40 and the second connecting electrode 50. The disconnector 9 for weak alternating short-circuit currents is disconnected from the circuit, and the wave current lightning does not leak through this disconnector. In this case, the disconnector 9 for weak alternating currents of a short circuit is protected and is not damaged by lightning discharges.

The protection device includes an arcing chamber 101. The first connecting electrode 40 and the second connecting electrode 50 are located opposite the arcing chamber 101 and determine the working gap of the arcing chamber 101. The arcing chamber 101 contains deionization plates 102 designed to cool the electric arc 100 and its extinction.

When weak alternating short-circuit currents flowing through the protective device, having an energy lower than the threshold breaking energy, said currents flow through the first connecting electrode 40, the third movable arc switching electrode 60 and the disconnector 9 for weak alternating short-circuit currents. The disconnector is calibrated to switch from an electrically on state to an electrically disconnected state.

The disconnector 9 for weak alternating currents of a short circuit can be a thermal disconnector. The disconnector 9 for weak alternating short-circuit currents is preferably a fuse.

According to a second embodiment of the invention (FIGS. 4-6), a voltage surge limiter 2 is electrically connected in series with a disconnector 9 for weak alternating short-circuit currents between the third movable arc switching electrode 60 and the second contact pad 51.

Therefore, when wave electric currents of lightning of the type 10/350 or 8/20 flow through the protection device, the electric arc 100 is very quickly transferred between the first connecting electrode 40 and the second connecting electrode 50, and the voltage surge limiter 2 and the disconnector 9 for weak alternating currents of short short circuits are simultaneously disconnected from the circuit, and the wave current of the lightning does not flow through the disconnector. In this case, the limiter and disconnector are protected and are not damaged by lightning discharges.

According to a first alternative embodiment, the voltage surge limiter 2 is electrically connected in series with the tripping device 3 of the at least one fuse jumper 9, 8. The drive means 10 continuously exerts a driving force Fd on the voltage surge limiter. If at least one of the fusible links is destroyed, then the voltage surge limiter 2 is moved by the movement force Fd. The movement of the limiter directly affects the actuator 7. The mechanism is released and moves the third movable arc switching electrode 60 with the forced execution of the constant opening of contacts 4, 6.

The drive means 10 (FIGS. 7-9) preferably comprises a spring. The spring is a coil spring, compressed and applies a driving force Fd directly to the variable resistor 21. In accordance with a specific embodiment, the variable resistor 21 is connected in series with the disconnecting device 3 via two connecting leads.

The first connection terminal is connected to the disconnecting device 3 by a flexible metal braid (not shown), and the second connection terminal is connected to the second terminal pad 51 by a hard contact pin, integral with at least one fused jumper.

A hard pin (Fig. 7) holds the variable resistor in the first position. The third movable arc switching electrode is in a position called the working position. When at least one of the fusible bridges melts, the hard contact pin breaks and releases the displacement of the variable resistor under the action of the displacement force Fd. As shown in Fig. 8, the variable resistor 21 moves and directly acts on the actuator 7. Indeed, as shown in Figs. 8 and 9, the variable resistor 21 comes into contact with the pressure bar 71 of the actuator 7, which is released to move the third movable arc switching electrode 60. The movement of the third electrode leads to a constant opening of the contacts 4, 6. Then, the third movable arc switching electrode 60 is in a position called the switching position.

The voltage surge limiter 2 can be electrically connected to the second terminal pad 51 by two fused jumper wires 9, 8.

The first fused jumper acts as a disconnector for weak alternating short circuit currents. In accordance with the embodiment of FIGS. 7-9, the hard contact pin connecting the variable resistor to the second contact pad 51 comprises a section that is calibrated so as to melt when short circuit currents with an energy below the threshold flow through the contact pin opening.

The second fused jumper 8 is melted in case of overheating of the limiter. A rigid contact pin connecting the variable resistor to the second contact pad 51 is welded to the second terminal of the variable resistor by a low-melting weld.

The operating mode of the first alternative embodiment remains unchanged if the variable resistor 21 is placed on a carriage or in a movable housing forming an integral unit with a variable resistor 21. Then, a moving force can be applied to the carriage or the movable housing instead of directly applying to the variable resistor. In addition, the carriage or the movable housing can act directly on the pressure bar 71 of the actuator 7.

According to a first alternative embodiment (Fig. 10), a high-current disconnector 11 is connected in series between the first connecting electrode 40 and the first contact pad 41. The high-current disconnector is configured to act on the actuator 7 to move the third movable arc switching electrode 60 and force a constant opening of electrical contacts 4, 6. High-current disconnector 11 is calibrated to unlock the actuator 7 when through An electric current with an energy higher than the threshold opening energy flows through the disconnector.

In accordance with a specific embodiment, the high-current disconnector 11 comprises an electromagnetic trip means or fusible element.

According to a third alternative embodiment (FIG. 11), a third movable arc switching electrode 60 is connected to the first connecting electrode 40 of the insulating part when the electrical contacts are closed. The insulating part forms a spark gap 22 connected in series with the variable resistor 21 of the voltage surge limiter 2. In the event of a lightning strike, the disconnector 9 for weak alternating short circuit currents is disconnected from the circuit when an electric arc 100 is transferred between the first connecting electrode 40 and the second connecting electrode 50.

In accordance with another alternative embodiment, the disconnecting device comprises a restoring means 72. The restoring means 72 allows the third electrode to be moved from a position called a switching position to a position called a working position. In other words, the closure of the contacts 4, 6 can be carried out mechanically with the help of the restoring means 72 after a constant opening of the said contacts.

Claims (16)

1. The device (1) surge protection containing
limiter (2) voltage spikes with non-linear elements that vary with voltage,
a disconnecting device (3) with electrical contacts (4, 6) arranged electrically in series with a voltage surge limiter (2), comprising
a first connecting electrode (40) electrically connected to the first contact pad (41),
a second connecting electrode (50) electrically connected to the second contact pad (51),
a third movable arc switching electrode (60) electrically connected to the second contact pad (51),
an actuator (7) moving the third movable arc switching electrode (60) to force the permanent opening of the electrical contacts (4, 6), when electric currents with an energy higher than the opening energy threshold flow through the protection device,
characterized in that it comprises a disconnector (9) from weak alternating short circuit currents connected in series between the third movable arc switching electrode (60) and the second contact pad (51),
wherein the disconnector is disconnected from the circuit when an electric arc (100) is transferred between the first connecting electrode (40) and the second connecting electrode (50),
the disconnector switches from the switched on electric state to the switched off electric state when alternating electric short-circuit currents flowing through it, having an energy lower than the threshold breaking energy, flow through it. 2. The device according to claim 1, characterized in that the disconnector (9) from weak alternating currents of short circuit is a thermal disconnector. 3. The device according to claim 2, characterized in that the disconnector (9) from weak alternating short-circuit currents is a fuse. 4. The device according to any one of claims 1 to 3, characterized in that the voltage surge limiter (2) is connected in series with the disconnector (9) from weak alternating short-circuit currents between the third movable arc switching electrode (60) and the second contact pad (51 ), while the limiter and the disconnector are simultaneously disconnected from the circuit when an electric arc (100) is transferred between the first connecting electrode (40) and the second connecting electrode (50). 5. The device according to claim 1, characterized in that the voltage surge limiter (2) is electrically connected in series with the disconnecting device (3) of at least one fuse jumper (9, 8), the drive means (10) provides a force (Fd ) to move the limiter (2) voltage surges in case of expansion of at least one fusible jumper, while the movement of the limiter acts directly on the actuator (7) to move the third movable electrode (60) switching the arc and forced Permanent opening of contacts (4, 6). 6. The device according to claim 5, characterized in that the drive means (10) contains a spring. 7. A device according to any one of claims 5 or 6, characterized in that the voltage surge limiter (2) is electrically connected to the second contact pad (51) by two fused bridges (9, 8), the first fused jumper serving as a disconnector (9) weak alternating currents of short circuit, and the second fuse jumper (8) melts in case of overheating of the limiter. 8. The device according to claim 7, characterized in that the second fusible jumper (8) is a low-melting weld. 9. The device according to claim 1, characterized in that the limiter (2) voltage surge contains a variable resistor (21). 10. The device according to claim 9, characterized in that the voltage surge limiter (2) comprises a variable resistor (21) connected in series with the spark gap (22). 11. The device according to claim 1, characterized in that between the first connecting electrode (40) and the first contact pad (41) a high current disconnector (11) is connected in series, which acts on the actuator (7) to move the third movable electrode (60) switching the arc and forcing the continuous opening of the contacts (4, 6). 12. The device according to claim 11, characterized in that the high-current disconnector (11) is calibrated to act on the actuator (7) when electric currents with an energy higher than the threshold opening energy flow through the disconnector. 13. Device according to any one of paragraphs.11 or 12, characterized in that the high-current disconnector (11) contains an electromagnetic disconnecting means. 14. Device according to any one of paragraphs.11 or 12, characterized in that the high-current disconnector (11) contains a fusible element. 15. Device according to any one of claims 1 to 3, characterized in that the third movable arc switching electrode (60) is connected to the first connecting electrode (40) by an insulating part forming a spark gap when the electrical contacts (4, 6) are closed. 16. Device according to any one of claims 1 to 3, characterized in that the third movable arc switching electrode (60) is in contact with the first connecting electrode (40) when the electrical contacts (4, 6) are closed.

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